Concentration of ores



Patented Nov. 3, 1925.

UNITED sTAT s PATENT OFFICE- CARL PIERCE LEWIS, OF BTJ'RLINGAME, CALIFORNIA, ASSIGNOR TO MINERALS SEPARA- TION NORTH AMERICAN CQRBORATION, OF NEW YORK, N. Y., A CORPORATION OF MARYLAND.

No Drawing.

To all whom it may concern: I

Be it known that I, CARL PIERCE Lewis, a citizen of the United States, and a resident of Burlingame, county of San Mateo, State of California, have invented certain new and useful Improvements in Concentration of Ores, of which the following is a specification. t

This invention relates to the froth-flotation concentration of ores, and is herein described as applied to the froth-flotation of certain ores with the aid of certain organic compounds containing sulphur. It has been found that the froth-flotation process is carried out much more efliciently when there are present in the ore pulp certain of the sulphur derivatives of carbonic acid such as those that yield anions and cat-ions in solution. According to the present invention,

the froth-flotation process is carried out with the aid of a sulphur derivative of carbonic acid in-an acid ore pulp, the requisite acidity being usually obtained through the presence of sulphuric acid in the pulp.

The amountof acid used may vary widely. Sometimes, in the case of an ore containing acid-soluble mineral enough has been used to dissolve a large proportion of the acidsoluble mineral, with the result that the re- 30. sulting metal-bearing pulp liquid carries it away. This may be precipitated, if desired, as is well known. Often, however, by a careful adjustni nt of conditions much less 7 acid can be use 85 For laboratory purposes potassium xanthate was prepared as follows:

5198.4 ramsof 88.5% caustic potash was dissolved in 524 grams ethyl alcohol (denatured #5 formula) at a temperature of 40 124 F., in a reflux condenser; The solution was cooled to 58 F; It contained a large excess of alcohol over the theoretical amount needed for the subsequent reactions. To

this was added, while stirring, and. in a coolin bath, the theoretical amount of carbon disulphide. The reaction was substantially instantaneous, producing-a thickpul of otas'sium xanthate. Thepulpwas coole an centrifuged in a laboratory machine,

yielding crystals containing about 20%.

of pine oil and there is obtained a precipi- '--'.:Dur1ng asev'en and one half hours run cononiv'rnn'rron OF oREs.

Application and March 31, 1924. Serial No. 703,260.

the mother liquorgave excellent results in flotation. It was found in cases where sulphuric acid was used "according to the present invention that the centrifuged material yielded better results than the uncentrifuged. It has also been found that excellent results can be obtained by using,

instead of a pure or ordinary xanthate, the

product obtained when concentrated al-' coholic potash is mixed one-third its volume.

tate by adding CS in an amount somewhat in ;excess. of that needed to combine with the ethyl alcohol present.

In one test a pulp of Anaconda slimes was agitated with sulphuric acid at the rate of 25 pounds per ton, and the pine-oil-xanthate complex mixture at the rate of 0.4 pound per ton. The results are shown in the following table:

Assn s 'Recovcu, "2.1m.

Heads 100.0. 2.88 0on0 81.9 8.64 97.1 Tails 88. 1 12 2. 9 0

to a pulpof Anaconda v The other reagents used were a mixture of hardwood creosote and kerosene acid sludge, 5.0 pounds, and sulphuric acid, 20p0unds per ton. The tails contained 0.15%. sul: phide-copper and 0.23% acid soluble copper, making a total of-0.38% recovered copper :figainst a normalof 0.61% recovered i th "absence of xanth r p on current Anaconda slimes at; the rate of one .hundred and eleven tons per twentyfour hours in a minerals separation standard -machine, from a feed containing 3.28%

0.26% being acid soluble copper there was recovered a .concentrate contain-- ing 11.43% cu; and 36.9% insolubles, -the latter being a proportion desirable for smelting. The tailings contained 0.29% copper of which 0.20%- was acid soluble copper. This test was run at a temperature of 82 F. using for reagents, 7.89 pounds of kerosene acid sludge, 21.6 pounds of chamber sulphuric acid, 2.36 pounds of hardwood creosote, and 2.92 pounds of a twenty per cent. solution of potassium xanthate in water, all quantities being in pounds per short ton of ore.

Anaconda old gravity-concentration tailing reground for flotation were treated at per ton of solids, 0.67 pounds of a 30% solution of potassium xanthate in water, 3.96 pounds of kerosene acid sludge, and 11.45 pounds of chamber sulphuric acid.

Having thus described certain embodiments of the invention what is claimed is 1. The process of concentrating ores which consists m agitating a suitable acid pulp of an ore with a mineral-frothing agent and a sulphur derivative of carbonic acld yielding anions and cations in solution to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, and separating the froth.

2. The process of concentrating oreswhich consists in agitating a suitable acid pulp of an ore with a mineral-frothing agent and a xanthate to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, and separating the froth.

3. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and a xanthate and sulphuric acid to produce b the action of both a mineral-bearing frot containing a large proportion of a mineral of the ore, and separating the froth.

4. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing, agent and a sulphur derivative of carbonic acid yielding anions and cations in solution and sulphuric acid to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, and

separating the froth.

In testimony whereof, I have aflixed my signature to this specification.

CARL PIERCE LEWIS. 

